loop2: detected capacity change from 0 to 256
==================================================================
BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff884029a0 of 8 bytes by task 19716 on cpu 0:
 data_alloc+0x216/0x2c0 kernel/printk/printk_ringbuffer.c:1082
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2266
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2326
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2360
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2370
 __ext4_msg+0x18e/0x1a0 fs/ext4/super.c:990
 __ext4_fill_super fs/ext4/super.c:5294 [inline]
 ext4_fill_super+0x2497/0x39e0 fs/ext4/super.c:5676
 get_tree_bdev+0x253/0x2e0 fs/super.c:1615
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5708
 vfs_get_tree+0x56/0x1d0 fs/super.c:1780
 do_new_mount+0x227/0x690 fs/namespace.c:3352
 path_mount+0x49b/0xb30 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 x64_sys_call+0x25c9/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff884029a0 of 8 bytes by task 19718 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2266
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2326
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2360
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2370
 set_capacity_an